1185 finally show ?thesis . |
1185 finally show ?thesis . |
1186 qed simp |
1186 qed simp |
1187 qed auto |
1187 qed auto |
1188 |
1188 |
1189 lemma sets_Collect_Cauchy[measurable]: |
1189 lemma sets_Collect_Cauchy[measurable]: |
1190 fixes f :: "nat \<Rightarrow> 'a => real" |
1190 fixes f :: "nat \<Rightarrow> 'a => 'b::{metric_space, second_countable_topology}" |
1191 assumes f[measurable]: "\<And>i. f i \<in> borel_measurable M" |
1191 assumes f[measurable]: "\<And>i. f i \<in> borel_measurable M" |
1192 shows "{x\<in>space M. Cauchy (\<lambda>i. f i x)} \<in> sets M" |
1192 shows "{x\<in>space M. Cauchy (\<lambda>i. f i x)} \<in> sets M" |
1193 unfolding Cauchy_iff2 using f by auto |
1193 unfolding metric_Cauchy_iff2 using f by auto |
1194 |
1194 |
1195 lemma borel_measurable_lim[measurable (raw)]: |
1195 lemma borel_measurable_lim[measurable (raw)]: |
1196 fixes f :: "nat \<Rightarrow> 'a \<Rightarrow> real" |
1196 fixes f :: "nat \<Rightarrow> 'a \<Rightarrow> 'b::{banach, second_countable_topology}" |
1197 assumes f[measurable]: "\<And>i. f i \<in> borel_measurable M" |
1197 assumes f[measurable]: "\<And>i. f i \<in> borel_measurable M" |
1198 shows "(\<lambda>x. lim (\<lambda>i. f i x)) \<in> borel_measurable M" |
1198 shows "(\<lambda>x. lim (\<lambda>i. f i x)) \<in> borel_measurable M" |
1199 proof - |
1199 proof - |
1200 def u' \<equiv> "\<lambda>x. lim (\<lambda>i. if Cauchy (\<lambda>i. f i x) then f i x else 0)" |
1200 def u' \<equiv> "\<lambda>x. lim (\<lambda>i. if Cauchy (\<lambda>i. f i x) then f i x else 0)" |
1201 then have *: "\<And>x. lim (\<lambda>i. f i x) = (if Cauchy (\<lambda>i. f i x) then u' x else (THE x. False))" |
1201 then have *: "\<And>x. lim (\<lambda>i. f i x) = (if Cauchy (\<lambda>i. f i x) then u' x else (THE x. False))" |
1202 by (auto simp: lim_def convergent_eq_cauchy[symmetric]) |
1202 by (auto simp: lim_def convergent_eq_cauchy[symmetric]) |
1203 have "u' \<in> borel_measurable M" |
1203 have "u' \<in> borel_measurable M" |
1204 proof (rule borel_measurable_LIMSEQ) |
1204 proof (rule borel_measurable_LIMSEQ_metric) |
1205 fix x |
1205 fix x |
1206 have "convergent (\<lambda>i. if Cauchy (\<lambda>i. f i x) then f i x else 0)" |
1206 have "convergent (\<lambda>i. if Cauchy (\<lambda>i. f i x) then f i x else 0)" |
1207 by (cases "Cauchy (\<lambda>i. f i x)") |
1207 by (cases "Cauchy (\<lambda>i. f i x)") |
1208 (auto simp add: convergent_eq_cauchy[symmetric] convergent_def) |
1208 (auto simp add: convergent_eq_cauchy[symmetric] convergent_def) |
1209 then show "(\<lambda>i. if Cauchy (\<lambda>i. f i x) then f i x else 0) ----> u' x" |
1209 then show "(\<lambda>i. if Cauchy (\<lambda>i. f i x) then f i x else 0) ----> u' x" |
1213 then show ?thesis |
1213 then show ?thesis |
1214 unfolding * by measurable |
1214 unfolding * by measurable |
1215 qed |
1215 qed |
1216 |
1216 |
1217 lemma borel_measurable_suminf[measurable (raw)]: |
1217 lemma borel_measurable_suminf[measurable (raw)]: |
1218 fixes f :: "nat \<Rightarrow> 'a \<Rightarrow> real" |
1218 fixes f :: "nat \<Rightarrow> 'a \<Rightarrow> 'b::{banach, second_countable_topology}" |
1219 assumes f[measurable]: "\<And>i. f i \<in> borel_measurable M" |
1219 assumes f[measurable]: "\<And>i. f i \<in> borel_measurable M" |
1220 shows "(\<lambda>x. suminf (\<lambda>i. f i x)) \<in> borel_measurable M" |
1220 shows "(\<lambda>x. suminf (\<lambda>i. f i x)) \<in> borel_measurable M" |
1221 unfolding suminf_def sums_def[abs_def] lim_def[symmetric] by simp |
1221 unfolding suminf_def sums_def[abs_def] lim_def[symmetric] by simp |
1222 |
1222 |
1223 no_notation |
1223 no_notation |